Overexpression of phospholipase D1 in human breast cancer tissues

Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine (PC) to produce phosphatidic acid (PA) and choline. PLD is a major enzyme implicated in important cellular processes, such as cell proliferation. We designed this study to investigate the expression of PLD in human breast carcinomas and non-malignant tissues using RT-PCR, Western blot analysis, immunohistochemistry and an Arf-dependent PLD activity assay. We examined about 550 bp of PCR product and 120 kDa of PLD protein. Our results showed that PLD protein and mRNA levels were overexpressed in 14 of 17 breast cancer tissues. We also observed increased expression by immunohistochemistry and Arf-dependent PLD activity in microsomes of human breast tumors, which correlated well with PLD expression. PLD expression was elevated in human breast tumors compared with normal breast tissues. These results implicate a possible role of PLD in human breast tumorigenesis and suggest that PLD may be useful as a marker for malignant disease in the breast.

Adjuvant doxorubicin and cyclophosphamide versus cyclophosphamide, methotrexate, and 5-fluorouracil chemotherapy in premenopausal women with axillary lymph node positive breast carcinoma

BACKGROUND

This randomized controlled trial was to determine whether a combination chemotherapy regimen that contains anthracycline (doxorubicin and cyclophosphamide [AC]) is superior to the conventional cyclophosphamide, methotrexate, and 5-fluorouracil [CMF] combination in premenopausal women with axillary lymph node positive Stage II breast carcinoma.

METHODS

Premenopausal women with lymph node positive breast carcinoma were stratified according to age (younger than 35 or 35 years or older) and the number of positive axillary lymph nodes (1-3, 4-9, or >/= 10) and then randomly assigned to receive either doxorubicin 40 mg/m(2) and cyclophosphamide 600 mg/m(2) intravenously (i.v.) every 3 weeks or cyclophosphamide 100 mg/m(2) orally on Days 1 through 14, methotrexate 40 mg/m(2) and 5-fluorouracil 500 mg/m(2) i.v. on Days 1 and 8 every 4 weeks. Both arms were scheduled for six cycles.

RESULTS

The median follow-up was 57 months. Eighteen of the 55 AC patients developed recurrence compared with 16 of the 69 CMF patients. The corresponding 5-year recurrence free survival rates were 64% and 78%, respectively (P = 0.12). The site of the first recurrence for AC patients was locoregional in 7%, distant in 22%, and combined in 4%. The corresponding data for the CMF arm were 4%, 16%, and 3%, respectively. Six AC patients died compared with 9 CMF patients. The corresponding 5-year survival rates were 90% and 86%, respectively (P = 0.96). More leukopenia (52%, mostly Grade 1-2) occurred in the CMF arm than in the AC arm (33%, P = 0.001), but no febrile episode was accompanied with leukopenia.

CONCLUSIONS

This study showed no difference between AC and CMF with respect to both disease free and overall survival rates in premenopausal women with axillary lymph node positive breast carcinoma.

US of mammographically detected clustered microcalcifications

PURPOSE

To determine whether ultrasonography (US) can depict breast masses associated with mammographically detected clustered microcalcifications and whether the visibility at US is different between benign and malignant lesions.

MATERIALS AND METHODS

Ninety-four patients with 100 mammographically detected microcalcification clusters prospectively underwent US with a 10- or 12-MHz transducer before mammographically guided presurgical hook-wire localization. The visibility of breast masses at US was correlated with histologic and mammographic findings.

RESULTS

Surgical biopsy revealed 62 benign lesions, 30 intraductal cancers, and eight invasive cancers. At US, breast masses associated with microcalcifications were seen in 45 (45%) of 100 cases. US depicted more breast masses associated with malignant (31 [82%] of 38) than with benign (14 [23%] of 62) microcalcifications (P: <.001). In malignant microcalcification clusters larger than 10 mm, US depicted associated breast masses in all 25 cases. There was no statistically significant difference in shape and distribution of calcific particles, as well as in breast composition, at mammography between US visible and invisible groups.

CONCLUSION

Given a known mammographic location, US with a high-frequency transducer can depict breast masses associated with malignant microcalcifications, particularly clusters larger than 10 mm. US can be used to visualize large clusters of microcalcifications that have a very high suspicion of malignancy.

Nonpalpable breast lesions: evaluation with power Doppler US and a microbubble contrast agent-initial experience

PURPOSE

To evaluate power Doppler ultrasonography (US) performed with a microbubble US contrast agent in the differentiation of nonpalpable breast lesions.

MATERIALS AND METHODS

Fifty nonpalpable breast lesions in 50 patients were prospectively evaluated with power Doppler US before and after injection of the contrast agent SH U 508A. Lesion vascularity and the morphology of vessels on US scans were analyzed and were correlated with histologic results.

RESULTS

Surgical excision revealed 22 cancers and 28 benign lesions. At nonenhanced power Doppler US, eight (36%) of 22 cancers and four (14%) of 28 benign lesions were vascular. At contrast agent-enhanced power Doppler US, 21 (95%) cancers and six (21%) benign lesions were vascular (P <.001). Irregular vessels were seen in three cancers and one benign lesion at nonenhanced power Doppler US and in 11 cancers and one benign lesion at contrast-enhanced power Doppler US. By using the presence of vascularity in the mass as the diagnostic criterion for malignancy, the sensitivity, specificity, and positive and negative predictive values of power Doppler US changed from 36%, 86%, 67%, and 63%, respectively, to 95%, 79%, 78%, and 96% after contrast agent injection.

CONCLUSION

Contrast-enhanced power Doppler US was superior to nonenhanced power Doppler US in the demonstration and characterization of tumor vascularity in nonpalpable breast lesions. Contrast-enhanced power Doppler US may be useful for the differentiation between nonpalpable breast cancers and benign tumors.

Molecular cloning and sequencing of rat Cdc42 GTPase cDNA

Cdc42 is a member of the Rho family of small GTP-ase and plays an important role in intracellular signaling pathways regulating cell morphology, motility and stimulation of DNA synthesis. We have isolated cDNA encoding Cdc42 from a rat brain cDNA library using PCR-cloning strategy. The sequence of isolated gene revealed an open reading frame of 576 nucleotides with the potential to encode a protein of 191 amino acids with a predicted molecular weight of 21 kD. The resulting sequence was incorporated into the GenBank with accession number, AF205635. Sequence analysis revealed that overall cDNA sequence identity is 96% with human G25K and 52% with rat Chp, a homologue of the GTPase human Cdc42Hs, and having one nucleotide difference from the mouse Cdc42. However, putative protein sequence was identical to the mouse and human brain Cdc42Hs. On expression of the cDNA in COS-7 cells, a protein molecular weight of 21 kD was detected in immunoblotting using anti-human Cdc42 antibodies. Therefore, these results suggest that the cDNA we are reporting is most likely the rat homologue of the GTPase human Cdc42.

Flow cytometric analysis of primary tumors and their corresponding metastatic nodes in breast cancer

Human breast carcinoma is biologically heterogeneous, and its clinical course may vary from one which is indolent to one which rapidly progresses. Although it is the metastasis rather than the primary tumor that ultimately overwhelms the patients, studies concerning the DNA pattern have focused on the primary tumors. This study was undertaken to identify heterogeneities between primary tumors and metastases, and to evaluate the prognostic significance of the ploidy pattern and the S-phase fraction (SPF) of metastatic nodes in axillary node positive patients. Seventy-four frozen specimens of the primary and corresponding metastatic nodes from 37 patients have been analyzed by flow cytometry and the SPF calculated. The results of ploidy pattern analysis in primaries revealed 25 diploidy (67.6%) and 12 aneuploidy (32.4%), while those in metastasis showed 17 diploidy (46.0%) and 20 aneuploidy (54.0%). The aneuploidy group in metastatic nodes had the poorer histological grade (85.0% vs. 15.0%, p = 0.02), and more mean metastatic nodes (5.75 +/- 2.10 vs. 3.05 +/- 1.56, p = 0.018), and more frequent lymphatic vessel invasion (65.0% vs. 11.8%, p = 0.031) than its counterpart. Decreased expression of ER (70.6% vs. 25.0% p = 0.006) and increased expression of c-erbB2 (65.0% vs. 23.5%, p = 0.012) were observed in the aneuploidy of metastatic nodes. The group with higher SPF in metastatic nodes had more metastatic nodes (5.47 +/- 2.31 vs. 4.00 +/- 1.78, p = 0.042), and the higher incidence of lymphatic vessel invasion (57.9% vs. 22.2%, p = 0.027), and poor histological grade (71.4% vs. 37.5%, p = 0.039). In conclusion, the cell populations in metastatic nodes revealed DNA pattern which differed from that of primary tumors. The ploidy pattern and SPF in metastatic nodes might be considered as discriminate measure for risk factors in breast cancer patients with positive axillary node.

Alcohol consumption, glutathione S-transferase M1 and T1 genetic polymorphisms and breast cancer risk

To evaluate the potential association between GSTM1 and GSTT1 genotypes and development of breast cancer, a hospital based case-control study was conducted in a South Korean study population consisting of 189 histologically confirmed incident breast cancer cases and their 189 age-matched control subjects with no present or previous history of cancer. A multiplex polymerase chain reaction method was used for the genotyping analyses and statistical evaluations were performed by unconditional logistic regression model. The GSTM1 null genotype was significantly associated with breast cancer risk in premenopausal women [odds ratio (OR) = 2.0, 95% confidence interval (CI) = 1-3.7], but not in the postmenopausal women (OR = 0.9, 95% CI = 0.5-1.9), nor in all women grouped together (OR = 1.3, 95% CI = 0.8-1.1). The GSTT1 null genotype posed a similar risk of breast cancer with an OR of 1.6 (95% CI = 1.0-2.5) for the total breast cancer group, OR of 1.7 (95% CI = 0.9-3.2) for pre-menopausal women, and OR of 1.3 (95% CI = 0.6-2.8) for post-menopausal women. The breast cancer risk associated with concurrent lack of both GSTM1 and GSTT1 genes was 2.2 (95% CI = 1.1-4.5), and the risk increased as the number of null genotype increased (P for trend = 0.03). When the data were stratified by the known risk factors of breast cancer, a significant interaction was observed between the GSTM1 genotypes and alcohol consumption (P for interaction = 0.03). An especially remarkable risk of breast cancer was observed for alcohol-consuming premenopausal women lacking both the GSTM1 and GSTT1 genes (OR = 5.3, 95% CI = 1.0-27.8) compared to those with both of the genes. Our findings thus suggest a novel gene-environment interaction which plays an important role in the individual susceptibility to breast cancer. p6

Metallic punctate densities in the breast after Chinese herbal treatment: mammographic findings

PURPOSE

To describe the mammographic features of metallic punctate densities seen in women who were treated with the herb go-yak for breast abscess and to explain the cause of these findings.

MATERIALS AND METHODS

Mammograms showing metallic punctate densities that appeared to be microcalcifications in 34 women were analyzed retrospectively with attention to the location, shape, distribution, and depth of the lesions. In all patients, go-yak was applied into the open wound after abscess drainage 6-42 years before mammography. In six patients, histopathologic specimens were obtained after needle localization.

RESULTS

Metallic densities were in the subareolar or central breast in 24 (71%) of 34 patients. The shape was predominantly round or punctate in all patients, but rod-shaped or linear lesions were found in seven patients. The distribution and depth of lesions were variable, but they extended to the subcutaneous fat in 29 patients (85%). A high concentration of lead was found in the histopathologic specimens and herb samples.

CONCLUSION

Lead deposits associated with go-yak treatment should be included in the differential diagnosis when the suspected microcalcifications are of unusually high density, are central in location, and extend into the subcutaneous fat in Asian women with a history of breast abscess.

Effect of protease inhibitor on ischemia-reperfusion injury to rat liver

Liver failure due to ischemia-reperfusion injury, believed to be closely related to the generation of oxygen-free radicals, is a serious problem during liver surgery. Gabexate mesilate, a synthetic protease inhibitor, suppresses the extracellular release of oxygen-free radicals in the microvascular endothelium. To determine its effects on ischemia-reperfusion injury to the liver, we performed experiments with rats. We divided the animals into two ischemia-reperfusion groups: an experimental group, which underwent ischemic injury for 30 minutes, along with the infusion of gabexate mesilate, and a control group, which underwent injury only. Each group was then divided into four subgroups: ischemic injury only and 60-, 120-, and 180-minute reperfusion injury. The test parameters were tumor necrosis factor alpha (TNFalpha) and interleukin-6 (IL-6) in serum and superoxide dismutase (SOD), catalase, and malondialdehyde (MDA) in liver and lung tissues. The experimental group had a significantly higher liver SOD and catalase levels and a significantly lower level of liver and lung MDA than the control groups. TNFalpha levels in the experimental groups were significantly lower during the early phase, but a comparison of IL-6 levels between the two groups yielded no differences. Levels of lung catalase and SOD were not significantly different between the two groups. We concluded that protease inhibitor suppressed liver ischemia-reperfusion injury, and that it was due to an increase of antioxidant or suppression of oxygen-free radicals. The roles of TNFalpha and IL-6 in liver reperfusion injury were not clear, though TNFalpha might have had an effect during the early phase. With liver ischemia-reperfusion injury, the mechanism of lung involvement might be different from that of liver involvement.

Detection of cancer in augmented breasts by positron emission tomography

OBJECTIVE

To assess the diagnostic efficiency of positron emission tomography with 18-fluorine fluorodeoxyglucose in detecting breast cancer in augmented breasts.

DESIGN

Retrospective study.

SETTING

University hospital, Korea.

SUBJECT

9 cases or 8 patients with breasts augmented with paraffin or silicone.

INTERVENTION

FDG-PET, mammography, and ultrasonography

RESULTS

The mammogram detected the breast cancer in only 1 of 3 patients, and ultrasonography gave a false positive result in 1 patient with an augmented breast. In contrast, PET predicted all the cancers and 5/6 benign lesions. 2/3 breast cancers had axillary FDG uptake interpreted as showing metastatic involvement, and in 1 case with cancer with no axillary lymph node involvement there was no FDG uptake in the axilla, which correlated with the pathological finding.

CONCLUSIONS

Although the high cost of PET makes its use as a screening test for all patients with augmented breasts unrealistic, it would be the best diagnostic choice if other methods failed.

Distributional patterns of phospholipase C isozymes in rat kidney

As the first step to investigate the physiological function of phospholipase C (PLC), we determined the distribution patterns of PLC isozymes in normal rat kidneys using Western blotting analysis and immunohistochemistry. Western blotting analysis was performed in four regions (cortex, outer stripe and inner stripe of the outer medulla, and the inner medulla). PLC-beta1 and beta3 were detected in the inner stripe of the outer medulla and the inner medulla. PLC-gamma1 was distributed homogeneously along the corticomedullary axis. PLC-gamma2 was observed in the medulla and PLC-delta1 showed a gradual increase from the cortex to the inner medulla. In contrast, no PLC-beta4 was detected in all regions. On immunohistochemistry, the immunoreactivities to PLC antibodies were observed as follows: PLC-beta1, from the thick ascending limb (TAL) to the inner medullary collecting tubule (IMCT); PLC-beta3, in the glomerulus (Glm), the ascending thin limb (ATL) and the collecting tubule; PLC-beta4, Glm, the proximal convoluted tubule (PCT), ATL, the distal convoluted tubule, the connecting tubule, and the collecting tubules; PLC-gamma1, PCT, TAL and IMCT; PLC-delta1, homogeneously from PCT to IMCT. PLC-beta3 immunoreactivities were detected in the nuclei of the TAL, ATL, outer medullary collecting tubule (OMCT) and IMCT. PLC-beta4 and gamma2 were observed in Glm, MTAL, ATL, OMCT and IMCT. These results suggest the intrarenal site-specific existence of PLC isozymes that may regulate kidney functions through the PLC-mediated signal transductions.

Expression of phospholipase C-gamma 1 and its transcriptional regulators in breast cancer tissues

BACKGROUND

PLC-gamma 1 is activated through direct interaction with growth factor receptor tyrosine kinase but little is known about the mechanisms controlling PLC-gamma 1 expression and its biological significance.

MATERIALS AND METHODS

Using immunoblotting, we evaluated PLC-gamma 1 protein overexpression in twenty breast cancer tissues. The expression of binding protein to GES1, GES2 and GES3, located in transcriptional regulator (GPE1) was found by electrophoretic mobility shift assay (EMSA). We also determined whether there was any correlation between prognostic factors (numbers of metastatic axillary nodes, histologic grade, c-erbB2, p53, and E-cadherin) and the overexpression of PLC-gamma 1 protein.

RESULT

On immunoblotting, 17 of 20 breast cancer tissues showed overexpression of PLC-gamma 1, a result of which was corresponded to that of immunohistochemistry. The binding proteins to GES1, GES2 and GES3 were overexpressed only when PLC-gamma 1 protein overexpression was apparent. Positive expression of E-cadherin only was significantly associated with PLC-gamma 1 protein overexpression (x = 0.607, p = 0.045).

CONCLUSION

GPE1 binding proteins might be the transcriptional regulator in PLC-gamma 1 overexpression and the relationship between expression of PLC-gamma 1 and E-cadherin would require further elucidation.

Diagnostic value of positron emission tomography for detecting breast cancer

Positron emission tomography (PET) is an imaging method that employs radionuclide and tomography techniques. PET has high sensitivity for detecting breast cancer, both the primary tumor and axillary node metastasis. From June 1995 to November 1996 a total of 27 patients underwent breast operations based on PET results at Seoul National University Hospital. Whole-body PET images were obtained beginning 60 minutes after injection of 370 MBq (10 mCi) 18F-fluorodeoxyglucose. Regional scans were also obtained with transmission images. We compared the PET results with those from the physical examination and mammography. All cases were histologically confirmed. The diagnostic accuracy of PET was excellent for the primary tumor mass (97%) compared with that of the physical examination (78%) and mammography (67%). For axillary lymph node metastasis, PET had outstanding detection accuracy (96%) compared with the physical examination and mammography (74% and 60%, respectively). Whole-body PET scans made it possible to see all of the metastatic lesions at a glance in cases of metastatic or recurrent breast cancer. There was a probable correlation between the standard uptake value (SUV) and the number of axillary lymph node metastases, but in this study statistical significance was not proved because of the small number of cases. PET also could detect breast cancer in paraffin-augmented breasts. We concluded that PET is a highly sensitive, accurate diagnostic tool for breast cancer and that SUV, after more studies, could be used as an important prognostic factor.

Overexpression of phospholipase C-gamma1 in rat 3Y1 fibroblast cells leads to malignant transformation

Phospholipase C-gamma1 (PLC-gamma1) mediates signals from various extracellular origins to evoke cellular events such as mitogenesis. Previously, we reported that PLC-gamma1 was highly expressed in colorectal cancer and familial adenomatous polyposis, suggesting that PLC-gamma1 might be oncogenic. In this study, we have established rat 3Y1 fibroblasts that overexpress whole PLC-gamma1 and src homology 2 (SH2)-SH2-SH3 domain of PLC-gamma1. These cells showed a transformed phenotype and were tumorigenic when transplanted into nude mice. These results indicate that overexpression of PLC-gamma1 could transform rat fibroblasts, and the transformation is mediated by SH2-SH2-SH3 domain of PLC-gamma1.

Abnormal expression of four novel molecular markers represents a highly aggressive phenotype in breast cancer. Immunohistochemical assay of p53, nm23, erbB-2, and cathepsin D protein

BACKGROUND

In view of the cumulative results to date, p53, nm23, erbB-2, and cathepsin D are the most promising investigational prognostic factors in breast cancer.

OBJECTIVES

The clinical utility of these molecular markers to predict recurrence was evaluated.

METHODS

Archival pathology tissues of 100 breast cancer patients were analyzed by immunohistochemical assay. Molecular biologic data were merged with clinicopathologic variables.

RESULTS

Thirty-two patients (32%) had recurrence of disease at a median follow-up of 48 months (range 26-72 months). Investigational factor expression had statistical correlation for recurrence with increasing coexpression: one variable 20.6%, two variables 34.2%, three variables 47.1%, four variables 80.0% (P = 0.003). In univariate analysis, lymph node metastasis, tumor size, erbB-2 protein overexpression, and loss of nm23 protein expression were significant variables to determine recurrence; in multivariate analysis, node status and tumor size emerged as the most significant variables for recurrence.

CONCLUSIONS

Coexpression of the studied investigational variables functioned as significant prognostic correlates for recurrence. These findings suggest that the studied investigational prognostic factors possess the ability to discriminate a highly aggressive phenotype in breast cancer.

Menstrual and reproductive factors related to the risk of breast cancer in Korea. Ovarian hormone effect on breast cancer

To support the ovarian hormone hypothesis in the etiology of breast cancer, a hospital-based case-control study with community controls was conducted to evaluate the relationship of intervals among menstrual and reproductive events to the risk of breast cancer in Korea. The cases were 190 breast cancer patients, who had been histologically diagnosed at Seoul National University Hospital from Jan. 1, 1993 to Jun. 30, 1994. Included were cancer-free women, who had undertaken the Gynecological examination at the same hospital (n=190). Women recruited for a survey of diabetes prevalence in Yonchon County, adjacent to Seoul City, were taken as a community control group (n=190). Information on menstrual and reproductive factors with other life-styles was collected through a direct interview by the well-trained interviewers. The adjusted odds ratios and the 95% confidence intervals were based on the unconditional logistic regression model. Likelihood ratio test for trend was applied for the ordinal variables. Early age at menarche, late age at natural menopause, late age at first full term pregnancy, and fewer number of full term pregnancies are independently associated with the high risk of breast cancer in Korea. Moreover, the interval between the age at menarche and the age at natural menopause of community controls (29.9+/-6.15 years) was significantly shortened compared to breast cancer cases (34.9+/-4.42 years). Particularly noteworthy was that intervals between the age at menarche and the age at first full term pregnancy of both control groups (9.0+/-3.72 years for hospital controls; 7.2+/-4.04 years for community controls) were significantly shortened compared to breast cancer cases (11.0+/-4.51 years). These findings support the hypothesis that the longer exposure to ovarian hormones during the reproductive years, the higher the risk of breast cancer.

Phosphoinositide-specific phospholipase C and mitogenic signaling

The importance of PLC activation in cell proliferation is evident from the fact that the hydrolysis of PtdIns(4,5)P2 is one of the early events that follow the interaction of many growth factors and mitogens with their respective receptors. However, the importance of PLC activation is not restricted to proliferation; it is one of the most common transmembrane signaling events elicited by receptors that regulate many other cellular processes, including differentiation, metabolism, secretion, contraction, and sensory perception. It is also clear that cell proliferation signaling does not always require PLC, as indicated by the fact that growth factors such as insulin and CSF-1 do not appear to elicit the hydrolysis of PtdIns(4,5)P2, even though the intracellular domains of their receptors carry a PTK domain and the receptors show topologies very similar to those of the PLC-activating growth factors PDGF, EGF, and FGF. The growth factor-dependent activation of PLC is initiated by the formation of a complex between the receptor PTK and PLC-gamma; the formation of this complex is mediated by a specific interaction between a tyrosine phosphate residue on the intracellular domain of PTK and the SH2 domain of PLC-gamma. The receptor PTK subsequently phosphorylates PLC-gamma, of which two distinct isozymes, PLC-gamma 1 and PLC-gamma 2, have been identified. Proliferation of T cells and B cells in response to the aggregation of their respective cell surface receptors is also accompanied by the activation of PLC-gamma isozymes at an early stage. Unlike growth factor receptors, the T cell and B cell receptors lack intrinsic PTK activity but associate with several non-receptor PTKs of the Src and Syk families. Although the specific kinases are not known, one or more of these enzymes phosphorylate and activate PLC-gamma 1 and PLC-gamma 2. Transduction of growth signals by G protein-coupled receptors such as those for thrombin or bombesin also requires PtdIns(4,5)P2 hydrolysis, which, in this instance, is mediated by PLC-beta isozymes. The PLC-beta subfamily consists of four distinct members: PLC-beta 1, PLC-beta 2, PLC-beta 3, and PLC-beta 4. Agonist interaction with specific G protein-coupled receptors causes the dissociation of Gq proteins into G alpha and G beta gamma subunits and the exchange of GDP bound to G alpha for GTP. The resulting GTP-bound G alpha subunit then activates PLC-beta isoforms by binding to the carboxyl-terminal region of the enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Significant prognostic factors by multivariate analysis of 3926 gastric cancer patients

Univariate and multivariate analyses of 3926 selected gastric cancer patients collected between 1981 and 1991 were made to confirm several clinicopathologic prognostic factors and to evaluate the effectiveness of postoperative immunochemotherapy with OK-432, 5-FU, and mitomycin C in stage III gastric cancer. Five-year survival rates for each category of prognostic variables were obtained; and in the univariate analysis, most of the factors (including age, depth of invasion, lymph node metastasis, location of primary tumor, histologic differentiation, and gross type except for sex) showed some significance. Multivariate analysis was conducted and verified significant prognostic factors. Depth of invasion and lymph node metastasis were found to be the most powerful factors (p < 0.001); gross type, location, and histologic differentiation were additional significant factors (p < 0.05). For postoperative treatment, immunochemosurgery was most effective in stage III patients (p < 0.05). In conclusion, we may predict a prognosis for gastric cancer more precisely on the basis of these independent prognostic factors, and immunochemosurgery may be a valuable means to treat advanced gastric cancer.

Incidence estimation of female breast cancer among Koreans

The authors conducted a nationwide survey to estimate the incidence rates of female breast cancer among Korean women in 1990-1991. We identified potential breast cancer cases based on the claims sent by medical care institutions throughout Korea to the Korea Medical Insurance Corporation (KMIC) from January 1988 to December 1989, whose diagnoses in the claims included one of the following diagnostic codes; ICD-9 174-175 (malignant neoplasms of the breast), 217 (benign neoplasms of the breast), 610-611 (benign mammary dysplasia and other disorders of the breast), 233 (carcinoma in situ of the breast and genito-urinary system), or 195-199 (malignant neoplasms with uncoded sites). In order to collect the final diagnosis of the potential cases, abstracting medical records was performed through visiting or mailing an abstracting format to the corresponding medical institutions. Thereafter oncologists reviewed the abstracting formats and confirmed the incident cases of female breast cancer among the potential breast cancer cases. Using these data from the KMIC, the incidence patterns of female breast cancer among Korean women were estimated as of July 1, 1988 to June 30, 1989. The incidence rate of female breast cancer adjusted for the Korean population was estimated to be 9.9 (95% confidence interval: 9.5-10.4). The cumulative rates for the ages 0-64 and 0-74 were 0.85% and 1.0%, respectively. The standardized rate for the world population was 10.9, which was lower than those of any other Asian country including China and Japan in 1983-1987.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis, structure, and antitumor activity of 1,3-dithiol- and 1,3-dithiolan-2-ylidenemalonatoplatinum(II) complexes

1,3-Dithiol- and 1,3-dithiolan-2-ylidenemalonatoplatinum(II) complexes A2Pt(OOC)2C = CR2 (A = NH3, cyclopropylamine (CPA) or A2 = ethylenediamine(EDA), trans(+/-)-1,2-diaminocyclohexane(DACH); R2 = -SCH = CHS-, -SCH2CH2S-) have been synthesized and subjected to in vivo assay for antitumor activity after characterization by means of elemental analysis, IR spectroscopy, and x-ray analysis. The molecular structure of (CPA)2Pt(OOC)2C = CSCH = CHS has been determined by x-ray diffraction: space group P2(1)/n, a = 7.955(1), b = 16.912(2), c = 15.116(2) A, beta = 102.74(1) degrees, z = 4, R = 0.032, Rw = 0.035. Among the Pt(II) complexes studied, biscyclopropylamineplatinum(II) complexes both of the above-mentioned dicarboxylate leaving groups exhibited much higher antitumor activity against the leukemia L1210 cell line compared with the known cisplatin.

Overexpression of phospholipase C-gamma 1 in familial adenomatous polyposis

Phosphoinositide-specific phospholipase C (PLC) isozymes occupy a central role in the signal transduction system by regulating various cellular processes including proliferation and differentiation. In the present study, we examined the contents of PLCs in colorectal adenomas, carcinomas, and normal mucosa obtained from 4 familial adenomatous polyposis patients to find out whether this enzyme plays any role in the pathogenesis of adenomas and/or carcinomas in familial adenomatous polyposis. Radioimmunoassay and immunoblot analysis revealed that in contrast to little difference in PLC-beta 1 and PLC-delta 1 content, a considerably higher level of PLC-gamma 1 was detected in 3 of 4 cases for adenoma and in all cases for carcinoma as compared to normal mucosa. The level of PLC-gamma 1 expression increased from normal mucosa to adenoma, and finally to carcinoma progressively. Immunohistochemical findings also confirmed this observation. Likewise, activity of PLC-gamma 1 was considerably higher in adenomas and carcinomas than in normal mucosa. These results suggest that PLC-gamma 1-mediated signal transduction may play a significant role in the progression of colorectal tumors in patients with familial adenomatous polyposis.

Elevated content of phospholipase C-gamma 1 in colorectal cancer tissues

BACKGROUND

Phospholipase C isozymes (PLC) play a role in ligand-mediated signal transduction for cellular activity, such as proliferation and differentiation. However, the biologic significance of their molecules in carcinogenesis or tumor progression is yet to be determined.

METHODS

Using PLC isozyme-specific antibodies, the relative content of PLC in human colorectal carcinomas and in normal colonic mucosa was examined.

RESULTS

Immunoreactive analysis revealed considerably higher levels of PLC-gamma 1 protein in 15 of 17 colorectal carcinomas and little difference in PLC-beta 1 or PLC-gamma 1 content compared with normal colorectal tissues. By radioimmunoassay and Western blotting, PLC-gamma 1 showed three-fold to fourfold more expression in carcinomas than that in normal tissues.

CONCLUSION

Although factors that might influence the level of PLC-gamma 1 expression in colorectal carcinomas still remain obscure, the fact that most colorectal carcinomas display elevated levels of PLC-gamma 1 expression implies that PLC-gamma 1 may play an important role in proliferation of colorectal carcinoma cells.